Sperm Shield Fends off Microbes, Helps Preserve Fertility

(HealthNewsDigest.com) - Athletes have helmets, drivers buckle up with seatbelts, and it turns out that moving sperm are protected too -- by a protein that forms an anti-microbial shield around the cells as they travel through the reproductive tract, researchers now report.

The findings suggest that boosting levels of the protein, called human beta-defensin 1 (DEFB1) in sperm might help improve male fertility. DEFB1 is found in many parts of the body, including the reproductive tract, but its role in regulating male fertility has not been investigated. Now, Ruiying Diao and colleagues show that the protein can be released from the reproductive tract, bind to sperm, and form a shield that protects male reproductive cells against viruses, bacteria and fungi. Diao and colleagues focused on male patients with one of two common causes of infertility: poor sperm motility (asthenozoospermia) or genital tract infection (leukocytospermia).

The researchers found that DEFB1 levels in both patient groups were reduced compared to men with normal, fertile sperm, suggesting DEFB1 might play a role in these conditions' pathogenesis, respectively. To further explore this, Diao and colleagues incubated recombinant DEFB1 (a chunk of the normal DEFB1 protein), with sperm cells from the infertile patients and observed that treated sperm had improved motility, working antimicrobial protection and increased egg-penetrating capacity. The results hint that it may be possible to develop drugs that treat defective sperm with recombinant DEFB1 protein.